An amplifier that provides linear amplification, as compared to an amplifier that operates in the saturation region, receives an input signal and generates an output signal having a predetermined amount of gain. The frequency components of the output signal are generally similar to the frequency components of the input signal.
In some applications, there is a requirement that an amplifier provide a constant gain across its entire frequency response or bandwidth. In some other applications, there is a requirement that the input terminals of the amplifier be capable of receiving a differential pair of signals and the output terminals of the amplifier be capable of outputting an amplified differential pair of signals.
It is difficult to fabricate a wide band amplifier on a die for use as an integrated circuit (IC). It is even more difficult to fabricate an ultra wide band amplifier on a die having a constant gain across a frequency band that spans from direct current (dc) up to a frequency in excess of 20 GHz. The present invention addresses such an amplifier.